Milah And Eretz Yisroel

וכרות עמו הברית.  A brit is referred to as a כרת, a cutting apart.  It seems to be an oxymoron, a brit joins people together?  Chazal connect the milah with inheriting Eretz Yisroel, what's the connection? 

A brit means to join together two parties.  How do two different parties join together? By each party giving something to the other one.  When each one cuts off a piece of themselves and gives it to the other, then they are united.  That is what it means a כריתת ברית, by "cutting" away a piece of one's self and giving it to another party, it creates an inseparable bond .  (This idea it says in the Gra in his perush on Sefer Yetzirah and in the Alter Rebbe in this week's parsha, so coming from both the Litvoks and Chassidim.)

 Avrohom is promised Eretz Yisroel many times in this weeks parsha.  However, the Rogatchover says that all the promises are not alike.  The Rogatchover says that in the beginning of the parsha Avrohom was promised the land as a מתנה.  At the brit bein habisarim, Avrohom was promised the land as a ירושה.  That is why in the beginning of  the parsha it uses a language of אתן\ אתננה but in the brit bein habisarim it says לָ֧תֶת לְךָ֛ אֶת־הָאָ֥רֶץ הַזֹּ֖את לְרִשְׁתָּֽהּ. Now the land is given as a yerusha.  That is why it is only now that Avrohom asks בַּמָּ֥ה אֵדַ֖ע כִּ֥י אִֽירָשֶֽׁנָּה.  He understood that he may receive Eretz Yisroel as a מתנה but he didn't fathom how he could receive it as a ירושה.  

What is the difference between a present and a inheritance?  There is no such thing as a free lunch.  If one receives a present, that means one to some degree did something to deserve it.  An inheritance comes without any effort from the recipient, one receives without doing anything. Avrohom understood that Hashem would promise him Eretz Yisroel as "reward" for his actions but how could it be his as an inheritance?  That was his question.  With this we can understand why the 10 nations are mentioned in this context.  The 7 nations represent the 7 middot that a person can perfect.  The additional 3 are the 3 faculties of חב"ד that are not with a person's grasp.  They have to be given as a yerusha. 

A milah also involves both an aspect of giving from our perspective and a giving from Hashem.  The Rambam rules Laws of Milah (3:8) that one who is מושך ערלתו has nullified the covenant of Avrohom.   Yet at the same time he rules in the Laws of Terumot (7:6) that such a person may eat teruma, meaning he is not considered an ערל.  (See Rogatchover Parshas Bo Ch. 12 and other places pointed to in the Frankel edition.)  We see that a person can nullify there side of the brit, but their is the bris coming from Hashem that can't be nullified by an individual.  This reflects the two aspects of Avrohom's receiving of Eretz Yisroel.  There is the aspect that he "earned" it, his giving to Hashem and then there is also the yerusha aspect where it completely comes from Hashem.  (Largely based off of Likutay Sichos volume 35.)